docs: def select_t(self, t=None, out=bool):
          """ Return a time index array
  
          Return a boolean or integer index array, hereafter called 'ind'
          The array refers to the reference time vector self.ddataRef['t']
  
          Parameters
          ----------
          t :     None / float / np.ndarray / list / tuple
              The time values to be selected:
                  - None : ind matches all time values
                  - float : ind is True only for the time closest to t
                  - np.ndarray : ind is True only for the times closest to t
                  - list (len()==2): ind is True for the times inside [t[0],t[1]]
                  - tuple (len()==2): ind is True for times outside ]t[0];t[1][
          out :   type
              Specifies the type of the output index array:
                  - bool : return a boolean array of shape (self.ddataRef['nt'],)
                  - int : return the array as integers indices
  
          Return
          ------
          ind :   np.ndarray
              The array of indices, of dtype specified by keywordarg out
  
          """
          assert out in [bool,int]
          ind = _select_ind(t, self._ddataRef['t'], self._ddataRef['nt'])
          if out is int:
              ind = ind.nonzero()[0]
          return ind